
Steam is generated in the boiler of a cogeneration plant at 8 MPa and 400C at a steady rate of 5 kg/s. In normal operation, steam expands in a turbine to a pressure of 0.4 MPa and is then routed to the process heater, where it supplies the process heat. Steam leaves the process heater as a saturated liquid and is pumped to the boiler pressure. In this mode, no steam passes through the condenser, which operates at 15 kPa.
Draw the schematic and T-S diagrams. Label the points by setting point 1 at the condenser outlet, point 2 at the 1st pump (after the condenser) outlet, point 3 at the process heater outlet, point 4 at the 2nd pump (after the process heater) outlet, point 5 at the boiler inlet (after mixing chamber), point 6 at the boiler outlet, point 7 at the process heater inlet (no throttle valve), and point 8 at the condenser inlet.
Use 2 decimal places for the enthalpy and other energies in solving and for the final answers. For the steam quality (x) and entropy (s), use 4 decimal places in solving. For the specific volume, use 6 decimal places.
IMPORTANT: USE THE STEAM TABLES FROM CENGEL'S BOOK ONLY (uploaded already in the files section).
If only 60 percent of the steam is routed to the process heater and the remainder is expanded to the condenser pressure, determine the following:
- Enthalpy at point 1 in kJ/kg =
- Enthalpy at point 2 in kJ/kg =
- Enthalpy at point 3 in kJ/kg =
- Enthalpy at point 4 in kJ/kg =
- Enthalpy at point 5 in kJ/kg =
- Enthalpy at point 6 in kJ/kg =
- Enthalpy at point 7 in kJ/kg =
- Enthalpy at point 8 in kJ/kg =
- Work turbine in kW =
- Rate at which process heat is supplied in kW =

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